President Barack Obama nominated Chief of Staff Jacob J. Lew to be the next Treasury secretary Thursday afternoon as expected, calling on Congress to confirm him as quickly as possible.

Standing in the White House flanked by Lew and outgoing Treasury Secretary Timothy F. Geithner, Obama called Lew a man of integrity and experience who would continue Geithner’s work.

“I trust his judgment. I value his friendship. I know very few people with greater integrity,” Obama said of Lew. He noted the nominee’s role in helping to negotiate the 1983 Social Security deal between Speaker Tip O’Neill and President Ronald Reagan, as well as his more recent posts as budget director and chief of staff.

Lew is “a low-key guy who prefers to surround himself with policy experts rather than television cameras,” Obama said, and “knows that every number on a page . . . has to be an expression of who we are as a nation, our values.”

Obama ticked off accomplishments under Geithner’s tenure, including rescuing the economy in his first months in office while recouping most of the Wall Street bailout money, saving the auto industry, helping homeowners and making the tax code less skewed to the wealthy.

“I had to personally get on my knees” to beg him to stay on a few years ago, the president said.

Plaudits started flowing in immediately for Lew from Capitol Hill, although Sen. Jeff Sessions of Alabama, the ranking Republican on the Budget Committee, has made no secret he intends to try to block the pick. Sessions has been especially critical of Lew’s role while in the budget post, accusing him of misleading the public about the debt.

“I believe that this man has been the architect of the Obama budget policy. I believe it’s very fundamentally wrong and I believe he has not been honest with the American people on it,” Sessions said on CNN.

Sen. Mike Lee, R-Utah, also ripped the pick, saying it “signals that the president will continue to pursue the same failed policies of the previous four years: higher taxes, more spending, and more debt. ... At a moment when the president could have shown a willingness to work with Republicans to fix the challenges that face the country, he has instead moved in a disappointing direction.”

Obama faced friendly fire from Sen. Bernard Sanders, I-Vt., who said in a statement he would vote against Lew citing his Wall Street ties. Sanders said virtually all of Obama’s key economic advisers have come from Wall Street.

“We need a treasury secretary who is prepared to stand up to corporate America and their powerful lobbyists and fight for policies that protect the working families in our country. I do not believe Mr. Lew is that person,” he said.

Sen. Orrin G. Hatch of Utah, the ranking Republican on Finance, said he had an open mind but wants more answers on how the administration will tackle the deficit.

“As I told the president yesterday, it’s imperative that Mr. Lew outline the administration’s plans on tackling our unsustainable debt, what areas of federal spending should be cut, and what kind of reforms — from our tax code to our entitlement programs —are needed to get our fiscal house in order,” Hatch said in a statement. “Since Mr. Lew participated in numerous budget negotiations with Congress and with four consecutive years of over $1 trillion deficits, the American people deserve to know not only that this nominee is qualified for the job, but also what policies the White House supports to get federal spending under control.”